package com.neuedu.ec.common;

import com.auth0.jwt.JWT;
import com.auth0.jwt.JWTCreator;
import com.auth0.jwt.algorithms.Algorithm;
import com.neuedu.ec.vo.WeChatUserInfo;
import com.sun.org.apache.xerces.internal.impl.dv.util.Base64;
import org.bouncycastle.jce.provider.BouncyCastleProvider;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.io.UnsupportedEncodingException;
import java.security.*;
import java.security.spec.InvalidParameterSpecException;
import java.util.Arrays;

public class WeChatUtils {

    //用于生成token 和解析token的 密钥，可以随便定义，两处保持一致即可
    public static final String JWT_KEY = "com.neuedu.ec.wechat";


    /**
     * 解密用户敏感数据获取用户信息
     * @param sessionKey 数据进行加密签名的密钥
     * @param encryptedData 包括敏感数据在内的完整用户信息的加密数据
     * @param iv 加密算法的初始向量
     */
    public static String getUserInfo(String encryptedData,String iv,String sessionKey){
        // 被加密的数据
        byte[] dataByte = Base64.decode(encryptedData);
        // 加密秘钥
        byte[] keyByte = Base64.decode(sessionKey);
        // 偏移量
        byte[] ivByte = Base64.decode(iv);
        try {
            // 如果密钥不足16位，那么就补足.  这个if 中的内容很重要
            int base = 16;
            if (keyByte.length % base != 0) {
                int groups = keyByte.length / base + (keyByte.length % base != 0 ? 1 : 0);
                byte[] temp = new byte[groups * base];
                Arrays.fill(temp, (byte) 0);
                System.arraycopy(keyByte, 0, temp, 0, keyByte.length);
                keyByte = temp;
            }
            // 初始化
            Security.addProvider(new BouncyCastleProvider());
            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS7Padding","BC");
            SecretKeySpec spec = new SecretKeySpec(keyByte, "AES");
            AlgorithmParameters parameters = AlgorithmParameters.getInstance("AES");
            parameters.init(new IvParameterSpec(ivByte));
            cipher.init(Cipher.DECRYPT_MODE, spec, parameters);// 初始化
            byte[] resultByte = cipher.doFinal(dataByte);
            if (null != resultByte && resultByte.length > 0) {
                String result = new String(resultByte, "UTF-8");
                return result;
            }
        }catch (NoSuchProviderException e) {
            e.printStackTrace();
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (BadPaddingException e) {
            e.printStackTrace();
        } catch (InvalidKeyException e) {
            e.printStackTrace();
        } catch (InvalidAlgorithmParameterException e) {
            e.printStackTrace();
        } catch (NoSuchPaddingException e) {
            e.printStackTrace();
        } catch (InvalidParameterSpecException e) {
            e.printStackTrace();
        } catch (IllegalBlockSizeException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        return null;
    }


    public static String getUserToken(WeChatUserInfo user){
        JWTCreator.Builder builder = JWT.create();

        String token = builder.withClaim("openId",user.getOpenId())
                    .withClaim("nickName",user.getNickName())
                    .withClaim("gender",user.getGender())
                    .withClaim("language",user.getLanguage())
                    .withClaim("city",user.getCity())
                    .withClaim("province",user.getProvince())
                    .withClaim("country",user.getCountry())
                    .withClaim("avatarUrl",user.getAvatarUrl())
                                .sign(Algorithm.HMAC256(JWT_KEY));
        return token;
    }


}
